U.S. patent application number 15/708949 was filed with the patent office on 2018-06-21 for channel reservation signal with new radio pdcch waveform.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Tamer Adel KADOUS, Jing SUN.
Application Number | 20180176946 15/708949 |
Document ID | / |
Family ID | 60703066 |
Filed Date | 2018-06-21 |
United States Patent
Application |
20180176946 |
Kind Code |
A1 |
SUN; Jing ; et al. |
June 21, 2018 |
CHANNEL RESERVATION SIGNAL WITH NEW RADIO PDCCH WAVEFORM
Abstract
Techniques for a channel reservation signal design with a new
radio (NR) physical downlink control channel waveform are provided.
A method for wireless communication includes determining one or
more orthogonal frequency division multiplexing (OFDM) symbols to
transmit channel reservation signals, and determining a plurality
of resources available for transmitting the channel reservation
signals during the OFDM symbol(s). The method further includes
selecting one set of resources within a plurality of resources to
transmit a channel reservation signal, and transmitting the channel
reservation signal in the selected set of resources to reserve a
portion of spectrum for communication. Another method for wireless
communication includes determining OFDM symbol(s) to monitor for
channel reservation signals, determining a plurality of resources
available for monitoring the channel reservation signals during the
OFDM symbol(s), and monitoring for one or more channel reservation
signals transmitted in a set of resources within the plurality of
resources.
Inventors: |
SUN; Jing; (San Diego,
CA) ; KADOUS; Tamer Adel; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
60703066 |
Appl. No.: |
15/708949 |
Filed: |
September 19, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62435570 |
Dec 16, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 88/02 20130101;
H04W 72/042 20130101; H04L 27/2626 20130101; H04W 72/14 20130101;
H04W 88/08 20130101; H04W 28/26 20130101; H04L 5/0053 20130101;
H04L 5/0007 20130101; H04L 5/0048 20130101; H04L 5/0083 20130101;
H04L 5/0037 20130101; H04L 5/0094 20130101 |
International
Class: |
H04W 72/14 20060101
H04W072/14; H04L 5/00 20060101 H04L005/00; H04W 72/04 20060101
H04W072/04; H04W 28/26 20060101 H04W028/26; H04L 27/26 20060101
H04L027/26 |
Claims
1. A method for wireless communication by an apparatus, comprising:
determining one or more orthogonal frequency division multiplexing
(OFDM) symbols to transmit channel reservation signals; determining
a plurality of resources available for transmitting the channel
reservation signals during the one or more OFDM symbols; selecting
one set of resources within the plurality of resources to transmit
a channel reservation signal; and transmitting the channel
reservation signal in the selected set of resources to reserve a
portion of spectrum for communication.
2. The method of claim 1, wherein: the plurality of resources for
the channel reservation signal transmission use a structure of a
downlink control channel; and the plurality of resources comprise
one or more control channel elements (CCEs).
3. The method of claim 1, further comprising: determining a
plurality of decoding candidates available for sending the channel
reservation signals, wherein each decoding candidate comprises one
or more control channel elements (CCEs); and selecting one of the
decoding candidates to use for sending the channel reservation
signal, wherein the selected set of resources comprises the CCEs of
the selected decoding candidate.
4. The method of claim 3, wherein selecting the one of the decoding
candidates comprises randomly selecting a decoding candidate from
the plurality of decoding candidates.
5. The method of claim 3, further comprising: identifying at least
one other decoding candidate used by another device for sending a
channel reservation signal; determining whether the selected
decoding candidate collides with the decoding candidate used by the
other device; and selecting another decoding candidate if there is
a collision.
6. The method of claim 3, wherein each CCE comprises one or more
physical resource blocks (PRBs) and wherein each PRB comprises a
demodulation reference signal (DMRS).
7. The method of claim 3, wherein determining the one or more OFDM
symbols comprises selecting a same set of OFDM symbols chosen by at
least another device for a channel reservation signal transmission
in order to align the channel reservation signal transmissions.
8. The method of claim 7, wherein the selected decoding candidate
is different from a decoding candidate used for the channel
reservation signal transmission of the other device.
9. The method of claim 1, wherein the channel reservation signal
comprises a first channel reservation signal that indicates the
communication is for sending a transmission, or a second channel
reservation signal that indicates the communication is for
receiving a transmission.
10. The method of claim 9, wherein the first channel reservation
signal comprises power control information regarding the
communication.
11. The method of claim 9, wherein the second channel reservation
signal comprises power control information of the second channel
reservation signal.
12. The method of claim 9, wherein: the first channel reservation
signal is transmitted at a same time as at least one other channel
reservation signal from another device; and the other channel
reservation signal indicates a communication of the other device is
for sending a transmission.
13. The method of claim 12, wherein the set of resources used for
the first channel reservation signal does not overlap with a set of
resources, within the plurality of resources, used for the other
channel reservation signal.
14. The method of claim 9, wherein: the second channel reservation
signal is transmitted at a same time as at least one other channel
reservation signal from another device; and the other channel
reservation signal indicates a communication of the other device is
for receiving a transmission.
15. The method of claim 14, wherein the set of resources used for
the second channel reservation signal does not overlap with a set
of resources, within the plurality of resources, used for the other
channel reservation signal.
16. The method of claim 1, further comprising: transmitting a grant
message to one or more user equipments (UEs) before transmitting
the channel reservation signal, wherein the grant message comprises
a grant for at least one of uplink or downlink communications and
indicates at least one of a time for each of the one or more UEs to
transmit a channel reservation signal, or a time for each of the
one or more UEs to monitor for a channel reservation signal.
17. The method of claim 1, wherein the apparatus is a base station
(BS) or a user equipment (UE).
18. A method for wireless communication by an apparatus,
comprising: determining one or more orthogonal frequency division
multiplexing (OFDM) symbols to monitor for channel reservation
signals; determining a plurality of resources available for
monitoring the channel reservation signals during the one or more
OFDM symbols; and monitoring for one or more channel reservation
signals transmitted in a set of resources within the plurality of
resources.
19. The method of claim 18, wherein at least one of the channel
reservation signals indicates that a communication during a portion
of a spectrum is for sending a transmission.
20. The method of claim 18, wherein at least one of the channel
reservation signals indicates that a communication during a portion
of a spectrum is for receiving a transmission.
21. The method of claim 18, wherein monitoring for the one or more
channel reservation signals comprises: determining a plurality of
decoding candidates in the set of resources available for sending
the one or more channel reservation signals, wherein each channel
reservation signal uses one of the plurality of decoding
candidates; and performing a blind decoding procedure across the
plurality of decoding candidates for the one or more channel
reservation signals.
22. The method of claim 21, wherein determining the one or more
OFDM symbols comprises selecting a same set of OFDM symbols chosen
by at least another device for monitoring for a channel reservation
signal in order to align monitoring of the channel reservation
signals.
23. The method of claim 21, wherein each decoding candidate
comprises one or more control channel elements (CCEs), wherein each
CCE comprises one or more physical resource blocks (PRBs), and
wherein each PRB comprises a demodulation reference signal
(DMRS).
24. The method of claim 23, further comprising: processing one of
the decoding candidates used for one of the channel reservation
signals based on the DMRSs.
25. The method of claim 18, wherein the plurality of resources
available for monitoring for the channel reservation signal use a
structure of a downlink control channel.
26. The method of claim 18, further comprising: monitoring for a
grant message in the plurality of resources; and determining, based
on a schedule in the grant message, a time for monitoring one or
more of the plurality of channel reservation signals.
27. The method of claim 18, wherein the apparatus comprises a base
station (BS) or a user equipment (UE).
28. An apparatus for wireless communication, comprising: means for
determining one or more orthogonal frequency division multiplexing
(OFDM) symbols to transmit channel reservation signals; means for
determining a plurality of resources available for transmitting the
channel reservation signals during the one or more OFDM symbols;
means for selecting one set of resources within the plurality of
resources to transmit a channel reservation signal; and means for
transmitting the channel reservation signal in the selected set of
resources to reserve a portion of spectrum for communication.
29. An apparatus for wireless communication, comprising: means for
determining one or more orthogonal frequency division multiplexing
(OFDM) symbols to monitor for channel reservation signals; means
for determining a plurality of resources available for monitoring
the channel reservation signals during the one or more OFDM
symbols; and means for monitoring for one or more channel
reservation signals transmitted in a set of resources within the
plurality of resources.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 62/435,570, filed Dec. 16, 2016, which
is assigned to the assignee hereof and hereby expressly
incorporated by reference herein.
BACKGROUND
I. Field of the Disclosure
[0002] Aspects of the present disclosure relate generally to
wireless communications systems, and more particularly, to a
channel reservation signal design based on new radio (NR) physical
downlink control channel (PDCCH).
II. Description of Related Art
[0003] Wireless communication systems are widely deployed to
provide various telecommunication services such as telephony,
video, data, messaging, and broadcasts. Typical wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources (e.g., bandwidth, transmit power).
Examples of such multiple-access technologies include Long Term
Evolution (LTE) systems, code division multiple access (CDMA)
systems, time division multiple access (TDMA) systems, frequency
division multiple access (FDMA) systems, orthogonal frequency
division multiple access (OFDMA) systems, single-carrier frequency
division multiple access (SC-FDMA) systems, and time division
synchronous code division multiple access (TD-SCDMA) systems.
[0004] In some examples, a wireless multiple-access communication
system may include a number of base stations, each simultaneously
supporting communication for multiple communication devices,
otherwise known as user equipment (UEs). In LTE or LTE-A network, a
set of one or more base stations may define an eNodeB (eNB). In
other examples (e.g., in a next generation or 5G network), a
wireless multiple access communication system may include a number
of distributed units (DUs) (e.g., edge units (EUs), edge nodes
(ENs), radio heads (RHs), smart radio heads (SRHs), transmission
reception points (TRPs), etc.) in communication with a number of
central units (CUs) (e.g., central nodes (CNs), access node
controllers (ANCs), etc.), where a set of one or more distributed
units, in communication with a central unit, may define an access
node (e.g., a new radio base station (NR BS), a new radio node-B
(NR NB), a network node, 5G NB, gNB, etc.). A base station or DU
may communicate with a set of UEs on downlink channels (e.g., for
transmissions from a base station or to a UE) and uplink channels
(e.g., for transmissions from a UE to a base station or distributed
unit).
[0005] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, national, regional, and even global level. An example of
an emerging telecommunication standard is new radio (NR), for
example, 5G radio access. NR is a set of enhancements to the LTE
mobile standard promulgated by Third Generation Partnership Project
(3GPP). It is designed to better support mobile broadband Internet
access by improving spectral efficiency, lowering costs, improving
services, making use of new spectrum, and better integrating with
other open standards using OFDMA with a cyclic prefix (CP) on the
downlink (DL) and on the uplink (UL) as well as support
beamforming, multiple-input multiple-output (MIMO) antenna
technology, and carrier aggregation.
[0006] However, as the demand for mobile broadband access continues
to increase, there exists a need for further improvements in NR
technology. Preferably, these improvements should be applicable to
other multi-access technologies and the telecommunication standards
that employ these technologies.
[0007] As the demand for mobile broadband access continues to
increase, using shared radio frequency spectrum (SRFS), which may
include unlicensed radio frequency spectrum (URFS), has been
considered to help solve the spectrum congestion problem for future
wireless needs, not only to meet the growing demand for mobile
broadband access, but also to advance and enhance the user
experience with mobile communications. However, the SRFS may carry
other transmissions, and therefore techniques such as listen before
talk (LBT) and clear channel assessment (CCA) may be used in an
effort prevent excessive interference. In certain scenarios,
wireless devices operating in a shared spectrum may be
asynchronous. It may be desirable to mitigate interference caused
by wireless devices operating in the scared spectrum.
SUMMARY
[0008] The systems, methods, and devices of the disclosure each
have several aspects, no single one of which is solely responsible
for its desirable attributes. Without limiting the scope of this
disclosure as expressed by the claims which follow, some features
will now be discussed briefly. After considering this discussion,
and particularly after reading the section entitled "Detailed
Description" one will understand how the features of this
disclosure provide advantages that include improved communications
between access points and stations in a wireless network.
[0009] Techniques for transmitting a channel reservation signal
based on a new radio (NR) physical downlink control channel (PDCCH)
waveform are described herein.
[0010] Certain aspects of the present disclosure provide a method
that may be performed, for example, by an apparatus (e.g., base
station, user equipment, etc.). The method generally includes
determining one or more orthogonal frequency division multiplexing
(OFDM) symbols to transmit channel reservation signals. The method
also includes determining a plurality of resources available for
transmitting the channel reservation signals during the one or more
OFDM symbols. The method further includes selecting one set of
resources within the plurality of resources to transmit a channel
reservation signal. The method further yet includes transmitting
the channel reservation signal in the selected set of resources to
reserve a portion of spectrum for communication.
[0011] Certain aspects of the present disclosure provide an
apparatus for wireless communication. The apparatus generally
includes means for determining one or more orthogonal frequency
division multiplexing (OFDM) symbols to transmit channel
reservation signals. The apparatus also includes means for
determining a plurality of resources available for transmitting the
channel reservation signals during the one or more OFDM symbols.
The apparatus further includes means for selecting one set of
resources within the plurality of resources to transmit a channel
reservation signal. The apparatus further yet includes means for
transmitting the channel reservation signal in the selected set of
resources to reserve a portion of spectrum for communication.
[0012] Certain aspects of the present disclosure provide an
apparatus for wireless communication. The apparatus generally
includes at least one processor and a memory coupled to the at
least one processor. The at least one processor is generally
configured to determine one or more orthogonal frequency division
multiplexing (OFDM) symbols to transmit channel reservation
signals. The at least one processor is also configured to determine
a plurality of resources available for transmitting the channel
reservation signals during the one or more OFDM symbols. The at
least one processor is further configured to select one set of
resources within the plurality of resources to transmit a channel
reservation signal. The at least one processor is further yet
configured to transmit the channel reservation signal in the
selected set of resources to reserve a portion of spectrum for
communication.
[0013] Certain aspects of the present disclosure provide a
computer-readable medium having computer executable code stored
thereon. The computer executable code generally includes code for
determining one or more orthogonal frequency division multiplexing
(OFDM) symbols to transmit channel reservation signals. The
computer executable code also includes code for determining a
plurality of resources available for transmitting the channel
reservation signals during the one or more OFDM symbols. The
computer executable code further includes code for selecting one
set of resources within the plurality of resources to transmit a
channel reservation signal. The computer executable code further
yet includes code for transmitting the channel reservation signal
in the selected set of resources to reserve a portion of spectrum
for communication.
[0014] Certain aspects of the present disclosure provide a method
that may be performed, for example, by an apparatus (e.g., base
station, user equipment, etc.). The method generally includes
determining one or more OFDM symbols to monitor for channel
reservation signals. The method also includes determining a
plurality of resources available for monitoring the channel
reservation signals during the one or more OFDM symbols. The method
further includes monitoring for one or more channel reservation
signals transmitted in a set of resources within the plurality of
resources.
[0015] Certain aspects of the present disclosure provide an
apparatus for wireless communication. The apparatus generally
includes means for determining one or more OFDM symbols to monitor
for channel reservation signals. The apparatus also includes means
for determining a plurality of resources available for monitoring
the channel reservation signals during the one or more OFDM
symbols. The apparatus further includes means for monitoring for
one or more channel reservation signals transmitted in a set of
resources within the plurality of resources.
[0016] Certain aspects of the present disclosure provide an
apparatus for wireless communication. The apparatus generally
includes at least one processor and a memory coupled to the at
least one processor. The at least one processor is generally
configured to determine one or more OFDM symbols to monitor for
channel reservation signals. The at least one processor is also
configured to determine a plurality of resources available for
monitoring the channel reservation signals during the one or more
OFDM symbols. The at least one processor is further configured to
monitor for one or more channel reservation signals transmitted in
a set of resources within the plurality of resources.
[0017] Certain aspects of the present disclosure provide a
computer-readable medium having computer executable code stored
thereon. The computer executable code generally includes code for
determining one or more OFDM symbols to monitor for channel
reservation signals. The computer executable code also includes
code for determining a plurality of resources available for
monitoring the channel reservation signals during the one or more
OFDM symbols. The computer executable code further includes code
for monitoring for one or more channel reservation signals
transmitted in a set of resources within the plurality of
resources.
[0018] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed, and this
description is intended to include all such aspects and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] So that the manner in which the above-recited features of
the present disclosure can be understood in detail, a more
particular description, briefly summarized above, may be had by
reference to aspects, some of which are illustrated in the appended
drawings. It is to be noted, however, that the appended drawings
illustrate only certain typical aspects of this disclosure and are
therefore not to be considered limiting of its scope, for the
description may admit to other equally effective aspects.
[0020] FIG. 1 is a block diagram conceptually illustrating an
example telecommunications system, in accordance with certain
aspects of the present disclosure.
[0021] FIG. 2 is a block diagram illustrating an example logical
architecture of a distributed RAN, in accordance with certain
aspects of the present disclosure.
[0022] FIG. 3 is a diagram illustrating an example physical
architecture of a distributed RAN, in accordance with certain
aspects of the present disclosure.
[0023] FIG. 4 is a block diagram conceptually illustrating a design
of an example BS and user equipment (UE), in accordance with
certain aspects of the present disclosure.
[0024] FIG. 5 is a diagram showing examples for implementing a
communication protocol stack, in accordance with certain aspects of
the present disclosure.
[0025] FIG. 6 illustrates an example of a DL-centric subframe, in
accordance with certain aspects of the present disclosure.
[0026] FIG. 7 illustrates an example of an UL-centric subframe, in
accordance with certain aspects of the present disclosure.
[0027] FIG. 8 illustrates an example frame structure that can be
used for a channel reservation signal exchange in NR, in accordance
with certain aspects of the present disclosure.
[0028] FIG. 9 is a flow diagram illustrating example operations
that may be performed by a transmitting node, in accordance with
certain aspects of the present disclosure.
[0029] FIG. 10 is a flow diagram illustrating example operations
that may be performed by a receiving node, in accordance with
certain aspects of the present disclosure.
[0030] FIG. 11 illustrates an example of a channel reservation
signal exchange in NR using resources in a UE-specific control
subband, in accordance with certain aspects of the present
disclosure.
[0031] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one aspect may be beneficially utilized on other
aspects without specific recitation.
DETAILED DESCRIPTION
[0032] Aspects of the present disclosure provide apparatus,
methods, processing systems, and computer readable mediums for new
radio (NR) (new radio access technology or 5G technology). NR may
support various wireless communication services, such millimeter
wave (mmW) targeting high carrier frequency (e.g. 60 GHz), massive
multiple input multiple output (MIMO), sub-6 GHz systems, etc.
[0033] In some cases, one or more nodes in such systems may
participate in an exchange of channel reservation signals to
reserve channel resources from the spectrum for a desired
communication (e.g., a transmission or reception). Such an exchange
may allow for coexistence across nodes.
[0034] Aspects of the present disclosure provide techniques and
apparatus for a channel reservation signal design based on a NR
PDCCH waveform. For example, an apparatus may determine one or more
orthogonal frequency division multiplexing (OFDM) symbols to
transmit channel reservation signals. The apparatus may also
determine a plurality of resources available for transmitting the
channel reservation signals. The plurality of resources may use a
NR physical downlink control channel (PDCCH) structure. The
apparatus may select one set of resources within the plurality of
resources to transmit a channel reservation signal, and transmit
the channel reservation signal in the selected set of resources to
reserve (e.g., access) a portion of spectrum (e.g., data channel)
for communication. The communication, for example, may be for
sending a transmission or receiving a transmission during the
portion of spectrum. The apparatus may further monitor for one or
more channel reservation signals transmitted in a set of resources
within the plurality of resources.
[0035] The following description provides examples, and is not
limiting of the scope, applicability, or examples set forth in the
claims. Changes may be made in the function and arrangement of
elements discussed without departing from the scope of the
disclosure. Various examples may omit, substitute, or add various
procedures or components as appropriate. For instance, the methods
described may be performed in an order different from that
described, and various steps may be added, omitted, or combined.
Also, features described with respect to some examples may be
combined in some other examples. For example, an apparatus may be
implemented or a method may be practiced using any number of the
aspects set forth herein. In addition, the scope of the disclosure
is intended to cover such an apparatus or method which is practiced
using other structure, functionality, or structure and
functionality in addition to or other than the various aspects of
the disclosure set forth herein. It should be understood that any
aspect of the disclosure disclosed herein may be embodied by one or
more elements of a claim. The word "exemplary" is used herein to
mean "serving as an example, instance, or illustration." Any aspect
described herein as "exemplary" is not necessarily to be construed
as preferred or advantageous over other aspects.
[0036] The techniques described herein may be used for various
wireless communication networks such as LTE, CDMA, TDMA, FDMA,
OFDMA, SC-FDMA and other networks. The terms "network" and "system"
are often used interchangeably. A CDMA network may implement a
radio technology such as Universal Terrestrial Radio Access (UTRA),
cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other
variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856
standards. A TDMA network may implement a radio technology such as
Global System for Mobile Communications (GSM). An OFDMA network may
implement a radio technology such as NR (e.g. 5G RA), Evolved UTRA
(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE
802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are
part of Universal Mobile Telecommunication System (UMTS). NR is an
emerging wireless communications technology under development in
conjunction with the 5G Technology Forum (5GTF). 3GPP Long Term
Evolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that
use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in
documents from an organization named "3rd Generation Partnership
Project" (3GPP). cdma2000 and UMB are described in documents from
an organization named "3rd Generation Partnership Project 2"
(3GPP2). The techniques described herein may be used for the
wireless networks and radio technologies mentioned above as well as
other wireless networks and radio technologies. For clarity, while
aspects may be described herein using terminology commonly
associated with 3G and/or 4G wireless technologies, aspects of the
present disclosure can be applied in other generation-based
communication systems, such as 5G and later, including NR
technologies.
[0037] New radio (NR) may refer to radios configured to operate
according to a new air interface (e.g., other than Orthogonal
Frequency Divisional Multiple Access (OFDMA)-based air interfaces)
or fixed transport layer (e.g., other than Internet Protocol (IP)).
NR may include Enhanced mobile broadband (eMBB) targeting wide
bandwidth (e.g., 80 MHz beyond), millimeter wave (mmW) targeting
high carrier frequency (e.g., 60 GHz), massive MTC (mMTC) targeting
non-backward compatible MTC techniques, sub-6 GHz systems, and
mission critical targeting ultra reliable low latency
communications (URLLC). For these general topics, different
techniques are considered, such as coding, low-density parity check
(LDPC), and polar. NR cell may refer to a cell operating according
to the new air interface or fixed transport layer. A NR Node B
(e.g., 5G Node B) may correspond to one or multiple transmission
reception points (TRPs).
Example Wireless Communications System
[0038] FIG. 1 illustrates an example wireless network 100 in which
aspects of the present disclosure may be performed. For example,
the wireless network may be a new radio (NR) or 5G network. As
illustrated in FIG. 1, the wireless network 100 may include a
number of BSs 110 and other network entities. BSs 110 in the
network may be configured in different synchronous modes and/or
associated with different operators. A BS may be a station that
communicates with UEs. Each BS 110 may provide communication
coverage for a particular geographic area. In 3GPP, the term "cell"
can refer to a coverage area of a Node B and/or a Node B subsystem
serving this coverage area, depending on the context in which the
term is used. In NR systems, the term "cell" and gNB, Node B, 5G
NB, AP, NR BS, NR BS, or TRP may be interchangeable.
[0039] In some examples, a cell may not necessarily be stationary,
and the geographic area of the cell may move according to the
location of a mobile base station. In some examples, the base
stations may be interconnected to one another and/or to one or more
other base stations or network nodes (not shown) in the wireless
network 100 through various types of backhaul interfaces such as a
direct physical connection, a virtual network, or the like using
any suitable transport network.
[0040] In general, any number of wireless networks may be deployed
in a given geographic area. Each wireless network may support a
particular radio access technology (RAT) and may operate on one or
more frequencies. A RAT may also be referred to as a radio
technology, an air interface, etc. A frequency may also be referred
to as a carrier, a frequency channel, etc. Each frequency may
support a single RAT in a given geographic area in order to avoid
interference between wireless networks of different RATs. In some
cases, NR or 5G RAT networks may be deployed.
[0041] A BS may provide communication coverage for a macro cell, a
pico cell, a femto cell, and/or other types of cell. A macro cell
may cover a relatively large geographic area (e.g., several
kilometers in radius) and may allow unrestricted access by UEs with
service subscription. A pico cell may cover a relatively small
geographic area and may allow unrestricted access by UEs with
service subscription. A femto cell may cover a relatively small
geographic area (e.g., a home) and may allow restricted access by
UEs having association with the femto cell (e.g., UEs in a Closed
Subscriber Group (CSG), UEs for users in the home, etc.). A BS for
a macro cell may be referred to as a macro BS. A BS for a pico cell
may be referred to as a pico BS. A BS for a femto cell may be
referred to as a femto BS or a home BS. In the example shown in
FIG. 1, the BSs 110a, 110b and 110c may be macro BSs for the macro
cells 102a, 102b and 102c, respectively. The BS 110x may be a pico
BS for a pico cell 102x. The BSs 110y and 110z may be femto BS for
the femto cells 102y and 102z, respectively. A BS may support one
or multiple (e.g., three) cells.
[0042] The wireless network 100 may also include relay stations. A
relay station is a station that receives a transmission of data
and/or other information from an upstream station (e.g., a BS or a
UE) and sends a transmission of the data and/or other information
to a downstream station (e.g., a UE or a BS). A relay station may
also be a UE that relays transmissions for other UEs. In the
example shown in FIG. 1, a relay station 110r may communicate with
the BS 110a and a UE 120r in order to facilitate communication
between the BS 110a and the UE 120r. A relay station may also be
referred to as a relay BS, a relay, etc.
[0043] The wireless network 100 may be a heterogeneous network that
includes BSs of different types, e.g., macro BS, pico BS, femto BS,
relays, etc. These different types of BSs may have different
transmit power levels, different coverage areas, and different
impact on interference in the wireless network 100. For example, a
macro BS may have a high transmit power level (e.g., 20 Watts)
whereas pico BS, femto BS, and relays may have a lower transmit
power level (e.g., 1 Watt).
[0044] The wireless network 100 may support synchronous or
asynchronous operation. For synchronous operation, the BSs may have
similar frame timing, and transmissions from different BSs may be
approximately aligned in time. For asynchronous operation, the BSs
may have different frame timing, and transmissions from different
BSs may not be aligned in time. The techniques described herein may
be used for both synchronous and asynchronous operation.
[0045] A network controller 130 may couple to a set of BSs and
provide coordination and control for these BSs. The network
controller 130 may communicate with the BSs 110 via a backhaul. The
BSs 110 may also communicate with one another, e.g., directly or
indirectly via wireless or wireline backhaul.
[0046] The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed
throughout the wireless network 100, and each UE may be stationary
or mobile. A UE may also be referred to as a mobile station, a
terminal, an access terminal, a subscriber unit, a station, a
Customer Premises Equipment (CPE), a cellular phone, a smart phone,
a personal digital assistant (PDA), a wireless modem, a wireless
communication device, a handheld device, a laptop computer, a
cordless phone, a wireless local loop (WLL) station, a tablet, a
camera, a gaming device, a netbook, a smartbook, an ultrabook, a
medical device or medical equipment, a biometric sensor/device, a
wearable device such as a smart watch, smart clothing, smart
glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a
smart bracelet, etc.), an entertainment device (e.g., a music
device, a video device, a satellite radio, etc.), a vehicular
component or sensor, a smart meter/sensor, industrial manufacturing
equipment, a global positioning system device, or any other
suitable device that is configured to communicate via a wireless or
wired medium. Some UEs may be considered evolved or machine-type
communication (MTC) devices or evolved MTC (eMTC) devices. MTC and
eMTC UEs include, for example, robots, drones, remote devices,
sensors, meters, monitors, location tags, etc., that may
communicate with a BS, another device (e.g., remote device), or
some other entity. A wireless node may provide, for example,
connectivity for or to a network (e.g., a wide area network such as
Internet or a cellular network) via a wired or wireless
communication link. Some UEs may be considered Internet-of-Things
(IoT) devices.
[0047] In FIG. 1, a solid line with double arrows indicates desired
transmissions between a UE and a serving BS, which is a BS
designated to serve the UE on the downlink and/or uplink. A finely
dashed line with double arrows indicates interfering transmissions
between a UE and a BS.
[0048] Certain wireless networks (e.g., LTE) utilize orthogonal
frequency division multiplexing (OFDM) on the downlink and
single-carrier frequency division multiplexing (SC-FDM) on the
uplink. OFDM and SC-FDM partition the system bandwidth into
multiple (K) orthogonal subcarriers, which are also commonly
referred to as tones, bins, etc. Each subcarrier may be modulated
with data. In general, modulation symbols are sent in the frequency
domain with OFDM and in the time domain with SC-FDM. The spacing
between adjacent subcarriers may be fixed, and the total number of
subcarriers (K) may be dependent on the system bandwidth. For
example, the spacing of the subcarriers may be 15 kHz and the
minimum resource allocation (called a `resource block`) may be 12
subcarriers (or 180 kHz). Consequently, the nominal FFT size may be
equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25,
2.5, 5, 10 or 20 megahertz (MHz), respectively. The system
bandwidth may also be partitioned into subbands. For example, a
subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may
be 1, 2, 4, 8 or 16 subbands for system bandwidth of 1.25, 2.5, 5,
10 or 20 MHz, respectively.
[0049] While aspects of the examples described herein may be
associated with LTE technologies, aspects of the present disclosure
may be applicable with other wireless communications systems, such
as NR.
[0050] NR may utilize OFDM with a CP on the uplink and downlink and
include support for half-duplex operation using TDD. A single
component carrier bandwidth of 100 MHz may be supported. NR
resource blocks may span 12 sub-carriers with a sub-carrier
bandwidth of 75 kHz over a 0.1 ms duration. Each radio frame may
consist of 50 subframes with a length of 10 ms. Consequently, each
subframe may have a length of 0.2 ms. Each subframe may indicate a
link direction (i.e., DL or UL) for data transmission and the link
direction for each subframe may be dynamically switched. Each
subframe may include DL/UL data as well as DL/UL control data. UL
and DL subframes for NR may be as described in more detail below
with respect to FIGS. 6 and 7. Beamforming may be supported and
beam direction may be dynamically configured. MIMO transmissions
with precoding may also be supported. MIMO configurations in the DL
may support up to 8 transmit antennas with multi-layer DL
transmissions up to 8 streams and up to 2 streams per UE.
Multi-layer transmissions with up to 2 streams per UE may be
supported. Aggregation of multiple cells may be supported with up
to 8 serving cells. Alternatively, NR may support a different air
interface, other than an OFDM-based. NR networks may include
entities such as central units (CUs) and/or distributed units
(DUs).
[0051] In some examples, access to the air interface may be
scheduled, wherein a scheduling entity (e.g., a base station)
allocates resources for communication among some or all devices and
equipment within its service area or cell. Within the present
disclosure, as discussed further below, the scheduling entity may
be responsible for scheduling, assigning, reconfiguring, and
releasing resources for one or more subordinate entities. That is,
for scheduled communication, subordinate entities utilize resources
allocated by the scheduling entity. Base stations are not the only
entities that may function as a scheduling entity. That is, in some
examples, a UE may function as a scheduling entity, scheduling
resources for one or more subordinate entities (e.g., one or more
other UEs). In this example, the UE is functioning as a scheduling
entity, and other UEs utilize resources scheduled by the UE for
wireless communication. A UE may function as a scheduling entity in
a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh
network example, UEs may optionally communicate directly with one
another in addition to communicating with the scheduling
entity.
[0052] Thus, in a wireless communication network with a scheduled
access to time-frequency resources and having a cellular
configuration, a P2P configuration, and a mesh configuration, a
scheduling entity and one or more subordinate entities may
communicate utilizing the scheduled resources.
[0053] As noted above, a RAN may include a CU and DUs. A NR BS
(e.g., gNB, 5G NB, NB, TRP, AP) may correspond to one or multiple
BSs. NR cells can be configured as access cells (ACells) or data
only cells (DCells). For example, the RAN (e.g., a central unit or
distributed unit) can configure the cells. DCells may be cells used
for carrier aggregation or dual connectivity, but not used for
initial access, cell selection/reselection, or handover. In some
cases DCells may not transmit synchronization signals--in some case
cases DCells may transmit SS. NR BSs may transmit downlink signals
to UEs indicating the cell type. Based on the cell type indication,
the UE may communicate with the NR BS. For example, the UE may
determine NR BSs to consider for cell selection, access, handover,
and/or measurement based on the indicated cell type.
[0054] FIG. 2 illustrates an example logical architecture of a
distributed radio access network (RAN) 200, which may be
implemented in the wireless communication system illustrated in
FIG. 1. A 5G access node 206 may include an access node controller
(ANC) 202. The ANC may be a central unit (CU) of the distributed
RAN 200. The backhaul interface to the next generation core network
(NG-CN) 204 may terminate at the ANC. The backhaul interface to
neighboring next generation access nodes (NG-ANs) may terminate at
the ANC. The ANC may include one or more TRPs 208 (which may also
be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, or some other
term). As described above, a TRP may be used interchangeably with
"cell."
[0055] The TRPs 208 may be a DU. The TRPs may be connected to one
ANC (ANC 202) or more than one ANC (not illustrated). For example,
for RAN sharing, radio as a service (RaaS), and service specific
AND deployments, the TRP may be connected to more than one ANC. A
TRP may include one or more antenna ports. The TRPs may be
configured to individually (e.g., dynamic selection) or jointly
(e.g., joint transmission) serve traffic to a UE.
[0056] The local architecture 200 may be used to illustrate
fronthaul definition. The architecture may be defined that support
fronthauling solutions across different deployment types. For
example, the architecture may be based on transmit network
capabilities (e.g., bandwidth, latency, and/or jitter).
[0057] The architecture may share features and/or components with
LTE. According to aspects, the next generation AN (NG-AN) 210 may
support dual connectivity with NR. The NG-AN may share a common
fronthaul for LTE and NR.
[0058] The architecture may enable cooperation between and among
TRPs 208. For example, cooperation may be preset within a TRP
and/or across TRPs via the ANC 202. According to aspects, no
inter-TRP interface may be needed/present.
[0059] According to aspects, a dynamic configuration of split
logical functions may be present within the architecture 200. As
will be described in more detail with reference to FIG. 5, the
Radio Resource Control (RRC) layer, Packet Data Convergence
Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium
Access Control (MAC) layer, and a Physical (PHY) layers may be
adaptably placed at the DU or CU (e.g., TRP or ANC, respectively).
According to certain aspects, a BS may include a central unit (CU)
(e.g., ANC 202) and/or one or more distributed units (e.g., one or
more TRPs 208).
[0060] FIG. 3 illustrates an example physical architecture of a
distributed RAN 300, according to aspects of the present
disclosure. A centralized core network unit (C-CU) 302 may host
core network functions. The C-CU may be centrally deployed. C-CU
functionality may be offloaded (e.g., to advanced wireless services
(AWS)), in an effort to handle peak capacity.
[0061] A centralized RAN unit (C-RU) 304 may host one or more ANC
functions. Optionally, the C-RU may host core network functions
locally. The C-RU may have distributed deployment. The C-RU may be
closer to the network edge.
[0062] A DU 306 may host one or more TRPs (edge node (EN), an edge
unit (EU), a radio head (RH), a smart radio head (SRH), or the
like). The DU may be located at edges of the network with radio
frequency (RF) functionality.
[0063] FIG. 4 illustrates example components of the BS 110 and UE
120 illustrated in FIG. 1, which may be used to implement aspects
of the present disclosure. One or more components of the BS 110 and
UE 120 may be used to practice aspects of the present disclosure.
For example, antennas 452, processors 466, 458, 464, and/or
controller/processor 480 of the UE 120 and/or antennas 434,
processors 430, 420, 438, and/or controller/processor 440 of the BS
110 may be used to perform the operations described herein and
illustrated with reference to FIGS. 9 and 10.
[0064] FIG. 4 shows a block diagram of a design of a BS 110 and a
UE 120, which may be one of the BSs and one of the UEs in FIG. 1.
For a restricted association scenario, the base station 110 may be
the macro BS 110c in FIG. 1, and the UE 120 may be the UE 120y. The
base station 110 may also be a base station of some other type. The
base station 110 may be equipped with antennas 434a through 434t,
and the UE 120 may be equipped with antennas 452a through 452r.
[0065] At the base station 110, a transmit processor 420 may
receive data from a data source 412 and control information from a
controller/processor 440. The control information may be for the
Physical Broadcast Channel (PBCH), Physical Control Format
Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel
(PHICH), Physical Downlink Control Channel (PDCCH), etc. The data
may be for the Physical Downlink Shared Channel (PDSCH), etc. The
processor 420 may process (e.g., encode and symbol map) the data
and control information to obtain data symbols and control symbols,
respectively. The processor 420 may also generate reference
symbols, e.g., for the PSS, SSS, and cell-specific reference
signal. A transmit (TX) multiple-input multiple-output (MIMO)
processor 430 may perform spatial processing (e.g., precoding) on
the data symbols, the control symbols, and/or the reference
symbols, if applicable, and may provide output symbol streams to
the modulators (MODs) 432a through 432t. Each modulator 432 may
process a respective output symbol stream (e.g., for OFDM, etc.) to
obtain an output sample stream. Each modulator 432 may further
process (e.g., convert to analog, amplify, filter, and upconvert)
the output sample stream to obtain a downlink signal. Downlink
signals from modulators 432a through 432t may be transmitted via
the antennas 434a through 434t, respectively.
[0066] At the UE 120, the antennas 452a through 452r may receive
the downlink signals from the base station 110 and may provide
received signals to the demodulators (DEMODs) 454a through 454r,
respectively. Each demodulator 454 may condition (e.g., filter,
amplify, downconvert, and digitize) a respective received signal to
obtain input samples. Each demodulator 454 may further process the
input samples (e.g., for OFDM, etc.) to obtain received symbols. A
MIMO detector 456 may obtain received symbols from all the
demodulators 454a through 454r, perform MIMO detection on the
received symbols if applicable, and provide detected symbols. A
receive processor 458 may process (e.g., demodulate, deinterleave,
and decode) the detected symbols, provide decoded data for the UE
120 to a data sink 460, and provide decoded control information to
a controller/processor 480.
[0067] On the uplink, at the UE 120, a transmit processor 464 may
receive and process data (e.g., for the Physical Uplink Shared
Channel (PUSCH)) from a data source 462 and control information
(e.g., for the Physical Uplink Control Channel (PUCCH) from the
controller/processor 480. The transmit processor 464 may also
generate reference symbols for a reference signal. The symbols from
the transmit processor 464 may be precoded by a TX MIMO processor
466 if applicable, further processed by the demodulators 454a
through 454r (e.g., for SC-FDM, etc.), and transmitted to the base
station 110. At the BS 110, the uplink signals from the UE 120 may
be received by the antennas 434, processed by the modulators 432,
detected by a MIMO detector 436 if applicable, and further
processed by a receive processor 438 to obtain decoded data and
control information sent by the UE 120. The receive processor 438
may provide the decoded data to a data sink 439 and the decoded
control information to the controller/processor 440.
[0068] The controllers/processors 440 and 480 may direct the
operation at the base station 110 and the UE 120, respectively. The
controller/processor 440 and/or other processors and modules at the
base station 110 may perform or direct, e.g., the execution of
various processes for the techniques described herein, such as
operations 900 in FIG. 9, operations 1000 in FIG. 10, etc. The
controller/processor 480 and/or other processors and modules at the
UE 120 may also perform or direct, e.g., the execution of the
processes for the techniques described herein, such as operations
900 in FIG. 9, operations 1000 in FIG. 10, etc. The memories 442
and 482 may store data and program codes for the BS 110 and the UE
120, respectively. A scheduler 444 may schedule UEs for data
transmission on the downlink and/or uplink.
[0069] FIG. 5 illustrates a diagram 500 showing examples for
implementing a communications protocol stack, according to aspects
of the present disclosure. The illustrated communications protocol
stacks may be implemented by devices operating in a in a 5G system
(e.g., a system that supports uplink-based mobility). Diagram 500
illustrates a communications protocol stack including a Radio
Resource Control (RRC) layer 510, a Packet Data Convergence
Protocol (PDCP) layer 515, a Radio Link Control (RLC) layer 520, a
Medium Access Control (MAC) layer 525, and a Physical (PHY) layer
530. In various examples the layers of a protocol stack may be
implemented as separate modules of software, portions of a
processor or ASIC, portions of non-collocated devices connected by
a communications link, or various combinations thereof. Collocated
and non-collocated implementations may be used, for example, in a
protocol stack for a network access device (e.g., ANs, CUs, and/or
DUs) or a UE.
[0070] A first option 505-a shows a split implementation of a
protocol stack, in which implementation of the protocol stack is
split between a centralized network access device (e.g., an ANC 202
in FIG. 2) and distributed network access device (e.g., DU 208 in
FIG. 2). In the first option 505-a, an RRC layer 510 and a PDCP
layer 515 may be implemented by the central unit, and an RLC layer
520, a MAC layer 525, and a PHY layer 530 may be implemented by the
DU. In various examples the CU and the DU may be collocated or
non-collocated. The first option 505-a may be useful in a macro
cell, micro cell, or pico cell deployment.
[0071] A second option 505-b shows a unified implementation of a
protocol stack, in which the protocol stack is implemented in a
single network access device (e.g., access node (AN), new radio
base station (NR BS), a new radio Node-B (NR NB), a network node
(NN), or the like.). In the second option, the RRC layer 510, the
PDCP layer 515, the RLC layer 520, the MAC layer 525, and the PHY
layer 530 may each be implemented by the AN. The second option
505-b may be useful in a femto cell deployment.
[0072] Regardless of whether a network access device implements
part or all of a protocol stack, a UE may implement an entire
protocol stack (e.g., the RRC layer 510, the PDCP layer 515, the
RLC layer 520, the MAC layer 525, and the PHY layer 530).
[0073] FIG. 6 is a diagram 600 showing an example of a DL-centric
subframe. The DL-centric subframe may include a control portion
602. The control portion 602 may exist in the initial or beginning
portion of the DL-centric subframe. The control portion 602 may
include various scheduling information and/or control information
corresponding to various portions of the DL-centric subframe. In
some configurations, the control portion 602 may be a physical DL
control channel (PDCCH), as indicated in FIG. 6. The DL-centric
subframe may also include a DL data portion 604. The DL data
portion 604 may sometimes be referred to as the payload of the
DL-centric subframe. The DL data portion 604 may include the
communication resources utilized to communicate DL data from the
scheduling entity (e.g., UE or BS) to the subordinate entity (e.g.,
UE). In some configurations, the DL data portion 604 may be a
physical DL shared channel (PDSCH).
[0074] The DL-centric subframe may also include a common UL portion
606. The common UL portion 606 may sometimes be referred to as an
UL burst, a common UL burst, and/or various other suitable terms.
The common UL portion 606 may include feedback information
corresponding to various other portions of the DL-centric subframe.
For example, the common UL portion 606 may include feedback
information corresponding to the control portion 602. Non-limiting
examples of feedback information may include an ACK signal, a NACK
signal, a HARQ indicator, and/or various other suitable types of
information. The common UL portion 606 may include additional or
alternative information, such as information pertaining to random
access channel (RACH) procedures, scheduling requests (SRs), and
various other suitable types of information. As illustrated in FIG.
6, the end of the DL data portion 604 may be separated in time from
the beginning of the common UL portion 606. This time separation
may sometimes be referred to as a gap, a guard period, a guard
interval, and/or various other suitable terms. This separation
provides time for the switch-over from DL communication (e.g.,
reception operation by the subordinate entity (e.g., UE)) to UL
communication (e.g., transmission by the subordinate entity (e.g.,
UE)). One of ordinary skill in the art will understand that the
foregoing is merely one example of a DL-centric subframe and
alternative structures having similar features may exist without
necessarily deviating from the aspects described herein.
[0075] FIG. 7 is a diagram 700 showing an example of an UL-centric
subframe. The UL-centric subframe may include a control portion
702. The control portion 702 may exist in the initial or beginning
portion of the UL-centric subframe. The control portion 702 in FIG.
7 may be similar to the control portion described above with
reference to FIG. 6. The UL-centric subframe may also include an UL
data portion 704. The UL data portion 704 may sometimes be referred
to as the payload of the UL-centric subframe. The UL portion may
refer to the communication resources utilized to communicate UL
data from the subordinate entity (e.g., UE) to the scheduling
entity (e.g., UE or BS). In some configurations, the control
portion 702 may be a physical DL control channel (PDCCH).
[0076] As illustrated in FIG. 7, the end of the control portion 702
may be separated in time from the beginning of the UL data portion
704. This time separation may sometimes be referred to as a gap,
guard period, guard interval, and/or various other suitable terms.
This separation provides time for the switch-over from DL
communication (e.g., reception operation by the scheduling entity)
to UL communication (e.g., transmission by the scheduling entity).
The UL-centric subframe may also include a common UL portion 706.
The common UL portion 706 in FIG. 7 may be similar to the common UL
portion 606 described above with reference to FIG. 6. The common UL
portion 706 may additional or alternative include information
pertaining to channel quality indicator (CQI), sounding reference
signals (SRSs), and various other suitable types of information.
One of ordinary skill in the art will understand that the foregoing
is merely one example of an UL-centric subframe and alternative
structures having similar features may exist without necessarily
deviating from the aspects described herein. In one example, a
frame may include both UL centric subframes and DL centric
subframes. In this example, the ratio of UL centric subframes to DL
subframes in a frame may be dynamically adjusted based on the
amount of UL data and the amount of DL data that are transmitted.
For example, if there is more UL data, then the ratio of UL centric
subframes to DL subframes may be increased. Conversely, if there is
more DL data, then the ratio of UL centric subframes to DL
subframes may be decreased.
Example Shared Spectrum Deployments
[0077] Example deployment scenarios for a shared spectrum, which
may include use of an unlicensed radio frequency spectrum, may
include operator-based deployments, a stand-alone mode of
operation, and/or a dual-connectivity mode of operation. In an
operator-based deployment, multiple operators may share a same
frequency band. A stand-alone mode of operation may include
inter-public land mobile network (PLMN) handover from a licensed
carrier. A dual-connectivity mode of operation may include
connectivity to a shared spectrum component carrier and to an
anchor carrier on licensed spectrum.
Access in Unlicensed Spectrum
[0078] Medium access in an unlicensed spectrum may involve a
dynamic listen before talk (LBT) procedure. Dynamic LBT procedures
may allow sharing of network resources (e.g., frequency resources)
on millisecond time scale. However, access to the medium may not be
guaranteed, for example, in an asynchronous system. For
asynchronous operation, the Node Bs (BSs) may have different frame
timings, and transmissions from different Node Bs may not be
aligned in time (e.g., one or more subframe and/or frame boundaries
of different Node Bs may not be contemporaneously aligned).
[0079] A Wi-Fi asynchronous system design may be optimized for
dynamic LBT procedures. In a Wi-Fi system, beacon transmissions
(overhead signals, reference signals) may be subject to LBT. The
periodic beacon signals may be "asynchronous" in nature. Beacon
transmissions may not be transmitted frequently and receiving
stations (STAs) may trigger asynchronous transmission of beacons in
a Wi-Fi system.
[0080] STA-based mobility may be needed in an effort to compensate
for poor radio resource management (RRM) due to, for example, the
asynchronous nature of beacon transmissions. Data transmissions may
each contain a preamble which may be used for synchronization and
detection of the data burst.
Access in Licensed Spectrum
[0081] In 4G/LTE, medium access may be optimized for the licensed
spectrum. Accordingly, "sensing" (e.g., monitoring or listening) to
determine whether another network node is occupying a same RF band
before communicating ("talking") on the RF band, in an effort to
avoid interference, may not be required. 4G/LTE systems instead use
a periodic transmission of overhead signals. RRM procedures exploit
the periodic transmission of these overhead signals. Measurement
reporting may be utilized for network-controlled mobility that may
take into consideration radio conditions and system loading.
[0082] Battery life of UEs may be prolonged using a discontinuous
reception (DRX) procedure, whereby a UE discontinuously receives
information. During a DRX period, a UE may power down most of its
circuitry, thereby saving power.
[0083] NR may be optimized for licensed spectrum. While 4G/LTE may
not support a fast on/off procedure, where a transmitter-BS may
communicate with a wireless device, quickly stop using portions of
the spectrum, and quickly reestablish communication, NR system
designs may support this feature.
Shared Spectrum Medium Access
[0084] A shared spectrum may attempt to minimize changes from the
operation of the NR licensed spectrum in an effort to speed-up
shared spectrum deployment. The shared spectrum may accommodate
periodic transmissions of overhead and/or common channels. The
shared spectrum may not make many changes to RRM and may exploit a
fast on/off procedure. According to one example, a BS may
communicate with a wireless device using a portion of the shared
spectrum and may stop use of the shared spectrum, for example, to
defer to a licensed transmitter. The BS may restart using the
spectrum when the licensed transmitter stops use of spectrum
resources.
[0085] Operation in a shared spectrum may include a network listen
function at a Node B (BS). Deployments may protect overhead and/or
common channels of other deployments. Stated otherwise, a node
associated with a first spectrum and first operator may protect
overhead and/or common channels transmitted by a node associated
with a second spectrum and a second operator.
[0086] In a shared spectrum, the configuration used by other
wireless devices may be learned by detecting and measuring a
neighboring Node B's discovery reference signals (DRS) and/or
broadcast channel (BCH). A DRS may include, for example, PSS, SSS,
CRS, and/or CSI-RS. The shared spectrum may not use an LBT
procedure for overhead signals and/or common channels.
[0087] A UE, operating in a shared spectrum, may perform an LBT
procedure in an effort to access non-protected resources.
[0088] A Spectrum Access System (SAS) may allocate channels within
and across tiers. These tiers may include, in order of priority,
(1) incumbent licensees; (2) Priority Access licensees (PALs); and
(3) General Authorized Access (GAA) operators. A shared spectrum
may complement SAS server functionality with over-the-air
mechanisms for channel selection.
Example Channel Reservation Signal with NR PDCCH Waveform
[0089] Channel reservation (CR) signals, in general, can be used to
reserve portions of spectrum for communication. For example,
certain wireless local area networks (e.g., WiFi) use the request
to send (RTS) and clear to send (CTS) signals for channel
reservation. Certain systems, such as NR, may also support a
channel reservation signal exchange between nodes to allow for
co-existence across the nodes. For example, in unlicensed and/or
shared spectrum use of NR, channel reservation signals can be used
to reduce collisions by transmissions across different nodes
accessing the unlicensed/shared spectrum. In some aspects, the
channel reservation signal exchange between nodes in NR may include
an exchange of pre-grant (PG) messages, channel reservation for
transmission (CR-T) signals, and channel reservation for reception
(CR-R) signals.
[0090] The PG message may be transmitted by a BS and may include
information indicating which nodes are scheduled for communication
and include a (UL or DL) grant for the communication. The CR-T
signals may announce the intent to transmit and include transmit
power (e.g., power control) information regarding the upcoming data
transmission. A node receiving a CR-T signal may determine (or
estimate), based on the transmit power information in the CR-T
signal, a level of interference it will receive from the
transmitting node when the transmitting node sends the data
transmission. The CR-R signals may announce the intent to receive a
data transmission, and include information indicating at least one
of the acceptable interference level (for the node transmitting the
CR-R signal) or the transmit power information of the CR-R signal.
A node receiving a CR-R signal may determine, based on the CR-R
signal, a level of interference it will generate when transmitting,
and determine whether the level of interference is acceptable to
the node transmitting the CR-R signal.
[0091] FIG. 8 illustrates an example frame structure 800 that can
be used for a channel reservation signal exchange in NR, according
to certain aspects of the present disclosure. As shown, the frame
structure 800 may include a PG message burst at 802, a CR-T signal
burst at 804, a CR-R signal burst at 806, and data transmission at
808.
[0092] One or more nodes (e.g., BSs) may transmit PG messages at
802 in order to schedule one or more other nodes (e.g., UEs) for
communication during a portion of spectrum (e.g., data channel) at
808. As described in more detail below, the PG messages may be
transmitted in parallel by one or more BSs (i.e., each PG message
may be orthogonal in frequency with respect to other PG messages).
The transmission of the PG messages may be followed by parallel
transmission (e.g., by BSs and/or UEs) of CR-T signals (at 804),
followed by parallel transmission (e.g., by BSs and/or UEs) of CR-R
signals (at 806). In some cases, nodes may be configured to monitor
for the CR-R/CR-T signals when the nodes are not scheduled for
transmission. That is, nodes that are scheduled for transmission of
CR-R signals at 806 may monitor for CR-T signals at 804. Similarly,
nodes that are scheduled for transmission of CR-T signals at 804
may monitor for CR-R signals at 806.
[0093] In general, the approaches in some systems, e.g., such as
WiFi, for transmitting channel reservation signals may not be
appropriate in other systems, such as NR. For example, in WiFi,
channel reservation signals (e.g., RTS/CTS) are generally
transmitted in small packets, each about the size of a preamble.
Transmitting such frames, however, in systems such as NR with large
amounts of nodes can cause a significant amount of collisions,
which in turn can degrade the detection of the channel reservation
signals at receivers. Accordingly, a new design waveform for
channel reservation signals in NR is desired.
[0094] Aspects of the present disclosure provide techniques and
apparatus for a channel reservation signal design based on NR
PDCCH.
[0095] FIG. 9 is a flow diagram illustrating example operations 900
that may be performed, for example, by a channel reservation (CR)
transmitting node (e.g., BS 110, UE 120, etc.), in accordance with
certain aspects of the present disclosure. Operations 900 may
begin, at 902, where the CR transmitting node determines one or
more OFDM symbols to transmit channel reservation signals.
[0096] At 904, the CR transmitting node determines a plurality of
resources available for transmitting the channel reservation
signals during the one or more OFDM symbols. The plurality of
resources may use the same structure as a NR PDCCH. At 906, the CR
transmitting node selects one set of resources within the plurality
of resources to transmit a channel reservation signal. At 908, the
CR transmitting node transmits the channel reservation signal
(e.g., CR-T or CR-R) in the selected set of resources to reserve a
portion of spectrum for communications. The portion of spectrum,
for example, may correspond to a channel (e.g., data channel) being
used for communications. Such communications may include sending a
transmission or receiving a transmission. In one aspect, the CR
transmitting node may send one CR signal (e.g., CR-T or CR-R) at a
time. That is, the CR transmitting node may transmit a CR-T signal
followed by a CR-R signal, or vice versa.
[0097] FIG. 10 is a flow diagram illustrating example operations
1000 that may be performed, for example, by a CR receiving node
(e.g., BS 110, UE 120, etc.), in accordance with certain aspects of
the present disclosure. Operations 1000 may begin, at 1002, where
the CR receiving node determines one or more OFDM symbols to
monitor for channel reservation signals (e.g., CR-T, CR-R, etc.).
At 1004, the CR receiving node determines a plurality of resources
available for monitoring for the channel reservation signals during
the one or more OFDM symbols. In one aspect, the plurality of
resources available for monitoring for the channel reservation
signals use a structure of a downlink control channel (e.g.,
NR-PDCCH). At 1006, the CR receiving node monitors for one or more
channel reservation signals transmitted in a set of resources
within the plurality of resources.
[0098] In certain aspects, the plurality of resources used for the
channel reservation signal transmission may use a structure of a
downlink control channel (e.g., PDCCH) and include one or more
control channel elements (CCEs). For example, in one aspect, the
plurality of resources may include the UE-specific control subband
in NR. The basic resource unit for the UE-specific PDCCH structure
in NR is generally the physical resource block (PRB). For example,
each NR PDCCH may occupy one or more NR-CCEs, and each NR-CCE may
include one or more PRBs. The set of PRBs used for a particular NR
PDCCH may be distributed over the control subband. A demodulation
reference signal may be embedded in each PRB, and use the same
beamforming as the control data in the PRB. The demodulation
reference signal may be used by the UE for demodulation of the
NR-PDCCH.
[0099] In general, for NR-PDCCH, different numbers of NR-CCEs may
form the resource for downlink control information (DCI). The
number of NR-CCEs in a NR-PDCCH generally refers to the NR-PDCCH's
aggregation level. The aggregation level generally configures the
coverage of the DCI and the amount of resource used for the DCI.
Further, similar to legacy LTE, for NR PDCCH, one or more search
spaces may be defined, where each search space includes a set of
decoding candidates with one or more aggregation levels.
[0100] According to certain aspects, the UE-specific control
subband in NR may be re-used for channel reservation signal
transmissions. That is, the transmission of channel reservation
signals in NR may apply similar PRB (with DRMS)/NR-CCE/decoding
candidate concepts as those used for transmission of UE-specific
DMRS based PDCCH in NR. In one aspect, the channel reservation
signal transmissions can use the same coding and/or rate matching
mechanism as NR-PDCCH. Compared to NR-PDCCH, however, the payload
size of the channel reservation signal transmissions may be smaller
(e.g., less information may be included in the channel reservation
signals compared to typical DCI in PDCCH). This may translate to a
lower aggregation level for CR transmission for the same coverage
as NR-PDCCH.
[0101] In one aspect, the channel reservation signal (e.g., CR-T
and/or CR-R) may occupy a set of resources used for one of the
NR-PDCCHs. That is, one of the NR-PDCCHs may be replaced with a
channel reservation signal. For the channel reservation signals, a
search space that includes a set of decoding candidates may be
defined. The channel reservation search space may be a common
search space that is known to all nodes (e.g., BSs, UEs) in the
communication system. For example, in one aspect, the search space
can be semi-statically configured via broadcast signaling. The
aggregation level used for each decoding candidate can be
controlled based on the desired channel reservation signal coverage
and control capacity.
[0102] According to certain aspects, the CR transmitting node may
determine a plurality of decoding candidates for sending the
channel reservation signals, where each decoding candidate includes
one or more CCEs. The CR transmitting node can select one of the
decoding candidates to use for sending the channel reservation
signal. In some cases, the selected decoding candidate may be
different from a decoding candidate used for the channel
reservation signal transmission of another CR transmitting node. In
some cases, the CR transmitting node may select the decoding
candidate by randomly selecting a decoding candidate from the
plurality of decoding candidates. The selected set of resources
within the plurality of resources may include the CCEs of the
selected decoding candidate. Each CCE may include one or more PRBs
and each PRB may include a DMRS. Once selected, the CR transmitting
node may generate a channel reservation packet, encode the packet
with CRC insertion and fill the CR signal in the decoding
candidate. The CR transmitting node may also multiplex DMRS in each
PRB of the decoding candidate, and transmit the beam. As noted, the
channel reservation signal may be a CR-T that indicates the
communication (e.g., during a portion of spectrum) is for sending a
transmission or a CR-R that indicates the communication (e.g.,
during a portion of spectrum) is for receiving a transmission.
[0103] In one aspect, when the CR receiving node monitors for
channel reservation signals, it may perform a blind decoding of all
decoding candidates in the channel reservation signal search space.
For example, the CR receiving node may determine (e.g., based on a
received configuration and/or higher layer signaling) a plurality
of decoding candidates in the set of resources available for
sending the channel reservation signals, where each channel
reservation signal uses one of the plurality of decoding
candidates. The CR receiving node may perform a blind decoding
procedure across the plurality of decoding candidates for the one
or more channel reservation signals. As noted, each decoding
candidate may include one or more CCEs, each CCE may include one or
more PRBs, and each PRB may include a DMRS.
[0104] The CR receiving node may process one of the decoding
candidates used for one of the channel reservation signals based on
the DMRSs. For example, the CR receiving node may use the DMRS
inside each PRB for channel estimation, and perform a log
likelihood ratio (LLR) computation for each PRB using the estimated
channel. The receiving node may stitch together the LLRs for each
decoding candidate and perform decoding. If the CRC passes, the
receiving node may log the content.
[0105] FIG. 11 illustrates an example of a channel reservation
signal exchange 1100 in NR using resources in a UE-specific control
subband, according to certain aspects of the present disclosure. In
this example, four links (e.g., eNB.sub.i to UE.sub.i for i=0, 1,
2, 3) between the eNB and UE are defined. The channel reservation
signal exchange 1100 includes a PG burst at 1102, CR-R burst at
1104, CR-T burst at 1106, and CR-R burst at 1108. Note, however,
that the depicted exchange 1100 is merely a reference example of a
channel reference signal exchange that can be used. Those of
ordinary skill in the art will recognize that other channel
reference signal exchange configurations can be used.
[0106] In some aspects, CR transmitting nodes may transmit a grant
message (e.g., such as a PG) to one or more devices (e.g., UEs,
eNBs, etc.) before transmitting the channel reservation signal. The
grant message may include a grant for at least one of uplink or
downlink communications, and may indicate at least one of a time
for each of the devices to transmit a channel reservation signal or
a time for each of the devices to monitor for a channel reservation
signal. Likewise, each device may monitor for a grant message in
the resources (e.g., UE-specific control subband resources), and
determine, based on a schedule in the grant message, a time for
monitoring for one or more channel reservation signals.
[0107] As shown in FIG. 11, for example, in the PG stage at 1102,
each eNB.sub.i sends a PG to a UE.sub.i. Note each eNB.sub.i is a
different transmitting node. The PG may schedule (e.g., include a
grant) the UE.sub.i for communication (e.g., during a data channel)
and may indicate whether the communication is a downlink
transmission (e.g., from the eNB.sub.i) or an uplink communication
(e.g., from the UE). For example, the PG for UE.sub.0 is for an
uplink communication to eNB.sub.0, the PG for UE.sub.1 is for a
downlink communication from eNB.sub.1, the PG for UE.sub.2 is for
an uplink communication to eNB.sub.2, and the PG for UE.sub.3 is
for a downlink communication from eNB.sub.3.
[0108] From each UE's perspective, the PGs can be in a PG search
space. In some cases, if the PG burst is shared with a normal grant
burst, the PG search space can be a subset of (or the same as) a
normal UE-specific or common search space the UE is monitoring
(e.g., to save decoding attempts by the UE).
[0109] For the CR-R/CR-T burst, a CR search space may be defined
that is common to all nodes. Each CR transmitting node may use one
decoding candidate in the search space for the CR-T and/or CR-R
transmission. In some cases, each CR transmitting node may select
separate decoding candidates for the CR-T and/or CR-R transmission.
At the CR-R burst at 1104, the eNB.sub.0 sends a CR-R to prepare
for data reception from UE.sub.0, UE.sub.1 sends a CR-R to prepare
for data reception from eNB.sub.1, eNB.sub.2 sends a CR-R to
prepare for data reception from UE.sub.2, and UE.sub.3 sends a CR-R
to prepare for data reception from UE.sub.3.
[0110] In one aspect, one or more transmitters of a channel
reservation signal may select the same set of OFDM symbols to align
the CR transmission. That is, a first CR transmitting node may
select a same set of OFDM symbols chosen by at least a second CR
transmitting node for a channel reservation signal transmission in
order to align the channel reservation signal transmissions (e.g.,
by the first and at least second CR transmitting nodes). For
example, as shown in FIG. 11, each CR-R transmission at 1104 may
use the same set of OFDM symbols, each CR-T transmission at 1106
may use the same set of OFDM symbols, and so on. In one aspect,
each decoding candidate used by a particular node for a CR-R/CR-T
transmission may not overlap (e.g., in frequency) with another
decoding candidate used by another node for a CR-R/CR-T
transmission. For example, as shown in FIG. 11, the decoding
candidates are not overlapping (e.g., are orthogonal). In some
aspects, however, techniques presented herein may allow for one or
more decoding candidates to overlap. In such cases, diversity
and/or beamforming techniques may be used to reduce collisions
between nodes transmitting the CR signals.
[0111] As mentioned above, one or more nodes may monitor for
CR-R/CR-T signals when the nodes are not transmitting. Referring to
the example in FIG. 11, UE.sub.0, eNB.sub.1, UE.sub.2 and eNB.sub.3
may monitor for the CR-R signals transmitted from eNB.sub.0,
UE.sub.1, eNB.sub.2 and UE.sub.3, respectively, at 1104. In one
aspect, one or more CR receiving nodes may select the same set of
ODFM symbols (e.g., as one or more other CR receiving nodes) to
monitor for channel reservation signals (e.g., in order to align
the monitoring between the CR receiving nodes). Once received, each
node may determine based on the information (e.g., transmit power
information of the CR-R and/or acceptable interference level of the
node transmitting the CR-R) embedded in the CR-R whether to accept
their respective PG and proceed with transmission during the
portion of the spectrum (e.g., data channel). For example, each CR
receiving node can determine, based on the transmit power
information, a pathloss measurement between itself and the CR
transmitting node. Based on the pathloss measurement, the CR
receiving node can determine the level of interference that will be
received by the CR transmitting node due to a data transmission
from the CR receiving node. If the determined level of interference
exceeds the acceptable level interference of the CR transmitting
node, the CR receiving node may decide to drop its PG.
[0112] As shown in FIG. 11, for example, at 1104, UE.sub.0 (e.g.,
CR receiving node) receives a CR-R from eNB.sub.0 (e.g., CR
transmitting node) for a pending uplink transmission to eNB.sub.0.
Similarly, at 1104, eNB.sub.3 (e.g., CR receiving node) receives a
CR-R from UE.sub.3 (e.g., CR transmitting node) for a pending
downlink transmission from eNB.sub.3. However, at 1106, UE.sub.0
refrains from transmitting a CR-T to eNB.sub.0 and eNB.sub.3
refrains from transmitting a CR-T to UE.sub.3. In this situation,
UE.sub.0 may have determined that the magnitude of interference for
its pending uplink data transmission would have exceeded the
acceptable level of interference for eNB.sub.0 (e.g., indicated in
the CR-R received from eNB.sub.0). Similarly, eNB.sub.3 may have
determined that the magnitude of interference for its pending
downlink communication would have exceeded the acceptable level of
interference for UE.sub.3 (e.g., indicated in the CR-R received
from UE.sub.3). Thus, at 1106, the CR-T burst may just include CR-T
transmissions from eNB.sub.1 and UE.sub.2, respectively. At 1108,
another CR-R burst occurs and includes CR-R transmissions from
UE.sub.1 and eNB.sub.2.
[0113] In aspects, one difference of CR transmission from PDCCH
transmission is that channel reservation transmissions may be
transmitted from different nodes. As such, in some cases, there may
be decoding candidate collisions when each node selects a decoding
candidate and transmits a channel reservation signal using the
selected decoding candidate. For example, the nodes may not be able
to dynamically use different decoding candidates to avoid
collisions as in the PDCCH case.
[0114] Accordingly, aspects presented herein provide techniques for
avoiding (or reducing) collisions between channel reservation
transmissions.
[0115] In one aspect, the CR transmitting node can use a randomized
decoding candidate for channel reservation signal transmissions.
That is, the CR transmitting node can randomly select a decoding
candidate from the plurality of decoding candidates in the channel
reservation signal search space. Using a randomized decoding
candidate selection procedure may be desirable for mmW systems in
NR. For example, in such systems, the collision problem may be less
severe as different transmitters are beamformed differently. Thus,
even if there is a collision on the NR-CCE usage, the interference
can be suppressed by beamforming.
[0116] In some aspects, a CR transmitting node may identify at
least one other decoding candidate used by another device (e.g.,
another CR transmitting node) for sending a channel reservation
signal. The CR transmitting node may determine whether the selected
decoding candidate collides with the decoding candidate used by the
other device, and select another decoding candidate if there is a
collision. For example, in one aspect, the CR transmitting node can
use a semi-static collision avoidance algorithm to reduce
collisions. In some cases, for example, a given node may use the
same decoding candidate for both CR-R and CR-T transmissions. CR
transmitting nodes, therefore, may monitor which decoding
candidates are used by other CR transmitting nodes, and if a
collision is detected (e.g., the node determines that a neighbor
node is using the same decoding candidate), CR transmitting nodes
can switch to a different decoding candidate. This approach may be
desirable for CR transmitting nodes that have a certain number of
active nodes in their neighborhood (e.g., within a threshold
proximity).
[0117] As such, the techniques presented herein enable nodes to
re-use the NR-PDCCH waveform for the transmission of channel
reservation signals. Doing so allows for the PDCCH processing in
hardware/firmware/software to be re-used for channel reservation
signals in NR, and may avoid the need for a new channel design in
NR.
[0118] As used herein, a phrase referring to "at least one of" a
list of items refers to any combination of those items, including
single members. As an example, "at least one of: a, b, or c" is
intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any
combination with multiples of the same element (e.g., a-a, a-a-a,
a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or
any other ordering of a, b, and c). Moreover, the term "or" is
intended to mean an inclusive "or" rather than an exclusive "or."
That is, unless specified otherwise, or clear from the context, the
phrase "X employs A or B" is intended to mean any of the natural
inclusive permutations. That is, the phrase "X employs A or B" is
satisfied by any of the following instances: X employs A; X employs
B; or X employs both A and B. In addition, the articles "a" and
"an" as used in this application and the appended claims should
generally be construed to mean "one or more" unless specified
otherwise or clear from the context to be directed to a singular
form.
[0119] The methods disclosed herein comprise one or more steps or
actions for achieving the described method. The method steps and/or
actions may be interchanged with one another without departing from
the scope of the claims. In other words, unless a specific order of
steps or actions is specified, the order and/or use of specific
steps and/or actions may be modified without departing from the
scope of the claims.
[0120] As used herein, the term "determining" encompasses a wide
variety of actions. For example, "determining" may include
calculating, computing, processing, deriving, investigating,
identifying, looking up (e.g., looking up in a table, a database or
another data structure), ascertaining and the like. Also,
"determining" may include receiving (e.g., receiving information),
accessing (e.g., accessing data in a memory) and the like. Also,
"determining" may include resolving, selecting, choosing,
establishing and the like.
[0121] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language claims,
wherein reference to an element in the singular is not intended to
mean "one and only one" unless specifically so stated, but rather
"one or more." Unless specifically stated otherwise, the term
"some" refers to one or more. All structural and functional
equivalents to the elements of the various aspects described
throughout this disclosure that are known or later come to be known
to those of ordinary skill in the art are expressly incorporated
herein by reference and are intended to be encompassed by the
claims. Moreover, nothing disclosed herein is intended to be
dedicated to the public regardless of whether such disclosure is
explicitly recited in the claims. No claim element is to be
construed under the provisions of 35 U.S.C. .sctn. 112, sixth
paragraph, unless the element is expressly recited using the phrase
"means for" or, in the case of a method claim, the element is
recited using the phrase "step for."
[0122] The various operations of methods described above may be
performed by any suitable means capable of performing the
corresponding functions. The means may include various hardware
and/or software component(s) and/or module(s), including, but not
limited to a circuit, an application specific integrated circuit
(ASIC), or processor. Generally, where there are operations
illustrated in figures, those operations may have corresponding
counterpart means-plus-function components with similar
numbering.
[0123] For example, means for determining, means for selecting,
means for performing, means for using, means for sending, means for
transmitting, means for receiving, means for configuring, means for
identifying, means for obtaining, means for aligning, means for
choosing, means for indicating, means for communicating, means for
controlling, means for monitoring, means for processing and/or
means for decoding may include one or more processors or other
elements, such as the transmit processor 420, controller/processor
440, receive processor 438, MOD/DEMOD 432 and/or antenna(s) 434 of
the base station 110 illustrated in FIG. 4, and/or the transmit
processor 464, the controller/processor 480, the receive processor
458, DEMOD/MOD 454 and/or antenna(s) 452 of the user equipment 120
illustrated in FIG. 4.
[0124] The various illustrative logical blocks, modules and
circuits described in connection with the present disclosure may be
implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or other
programmable logic device (PLD), discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor may be a microprocessor, but in the alternative, the
processor may be any commercially available processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0125] If implemented in hardware, an example hardware
configuration may comprise a processing system in a wireless node.
The processing system may be implemented with a bus architecture.
The bus may include any number of interconnecting buses and bridges
depending on the specific application of the processing system and
the overall design constraints. The bus may link together various
circuits including a processor, machine-readable media, and a bus
interface. The bus interface may be used to connect a network
adapter, among other things, to the processing system via the bus.
The network adapter may be used to implement the signal processing
functions of the PHY layer. In the case of a user terminal 120 (see
FIG. 1), a user interface (e.g., keypad, display, mouse, joystick,
etc.) may also be connected to the bus. The bus may also link
various other circuits such as timing sources, peripherals, voltage
regulators, power management circuits, and the like, which are well
known in the art, and therefore, will not be described any further.
The processor may be implemented with one or more general-purpose
and/or special-purpose processors. Examples include
microprocessors, microcontrollers, DSP processors, and other
circuitry that can execute software. Those skilled in the art will
recognize how best to implement the described functionality for the
processing system depending on the particular application and the
overall design constraints imposed on the overall system.
[0126] If implemented in software, the functions may be stored or
transmitted over as one or more instructions or code on a
computer-readable medium. Software shall be construed broadly to
mean instructions, data, or any combination thereof, whether
referred to as software, firmware, middleware, microcode, hardware
description language, or otherwise. Computer-readable media include
both computer storage media and communication media including any
medium that facilitates transfer of a computer program from one
place to another. The processor may be responsible for managing the
bus and general processing, including the execution of software
modules stored on the machine-readable storage media. A
computer-readable storage medium may be coupled to a processor such
that the processor can read information from, and write information
to, the storage medium. In the alternative, the storage medium may
be integral to the processor. By way of example, the
machine-readable media may include a transmission line, a carrier
wave modulated by data, and/or a computer readable storage medium
with instructions stored thereon separate from the wireless node,
all of which may be accessed by the processor through the bus
interface. Alternatively, or in addition, the machine-readable
media, or any portion thereof, may be integrated into the
processor, such as the case may be with cache and/or general
register files. Examples of machine-readable storage media may
include, by way of example, RAM (Random Access Memory), flash
memory, ROM (Read Only Memory), PROM (Programmable Read-Only
Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM
(Electrically Erasable Programmable Read-Only Memory), registers,
magnetic disks, optical disks, hard drives, or any other suitable
storage medium, or any combination thereof. The machine-readable
media may be embodied in a computer-program product.
[0127] A software module may comprise a single instruction, or many
instructions, and may be distributed over several different code
segments, among different programs, and across multiple storage
media. The computer-readable media may comprise a number of
software modules. The software modules include instructions that,
when executed by an apparatus such as a processor, cause the
processing system to perform various functions. The software
modules may include a transmission module and a receiving module.
Each software module may reside in a single storage device or be
distributed across multiple storage devices. By way of example, a
software module may be loaded into RAM from a hard drive when a
triggering event occurs. During execution of the software module,
the processor may load some of the instructions into cache to
increase access speed. One or more cache lines may then be loaded
into a general register file for execution by the processor. When
referring to the functionality of a software module below, it will
be understood that such functionality is implemented by the
processor when executing instructions from that software
module.
[0128] Also, any connection is properly termed a computer-readable
medium. For example, if the software is transmitted from a website,
server, or other remote source using a coaxial cable, fiber optic
cable, twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared (IR), radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of medium. Disk and disc, as used herein, include
compact disc (CD), laser disc, optical disc, digital versatile disc
(DVD), floppy disk, and Blu-ray.RTM. disc where disks usually
reproduce data magnetically, while discs reproduce data optically
with lasers. Thus, in some aspects computer-readable media may
comprise non-transitory computer-readable media (e.g., tangible
media). In addition, for other aspects computer-readable media may
comprise transitory computer-readable media (e.g., a signal).
Combinations of the above should also be included within the scope
of computer-readable media.
[0129] Thus, certain aspects may comprise a computer program
product for performing the operations presented herein. For
example, such a computer program product may comprise a
computer-readable medium having instructions stored (and/or
encoded) thereon, the instructions being executable by one or more
processors to perform the operations described herein.
[0130] Further, it should be appreciated that modules and/or other
appropriate means for performing the methods and techniques
described herein can be downloaded and/or otherwise obtained by a
user terminal and/or base station as applicable. For example, such
a device can be coupled to a server to facilitate the transfer of
means for performing the methods described herein. Alternatively,
various methods described herein can be provided via storage means
(e.g., RAM, ROM, a physical storage medium such as a compact disc
(CD) or floppy disk, etc.), such that a user terminal and/or base
station can obtain the various methods upon coupling or providing
the storage means to the device. Moreover, any other suitable
technique for providing the methods and techniques described herein
to a device can be utilized.
[0131] It is to be understood that the claims are not limited to
the precise configuration and components illustrated above. Various
modifications, changes and variations may be made in the
arrangement, operation and details of the methods and apparatus
described above without departing from the scope of the claims.
* * * * *